Flask WTForms 自定义验证器不工作答案

【问题标题】：Flask WTForms Custom Validator Not WorkingFlask WTForms 自定义验证器不工作
【发布时间】：2020-02-12 22:22:47
【问题描述】：

此自定义验证器应检查 2 个数据库，以查看表单中输入的值是否与名为 training_name 和 date 的列中的值相同。但是，如果我输入数据库中存在的重复记录，则不会引发错误。请指教

class add_training_form(FlaskForm): #All fields are required
    training_course = SelectField('Training Course', choices=[], validators=[DataRequired()]) #The choices will be assigned in route
    training_provider = SelectField('Training Provider', choices=[], validators=[DataRequired()])
    date = DateField('Date of Training', validators=[DataRequired()])
    cpd = IntegerField('CPD hours',validators=[DataRequired(message='Invalid input')] )
    certificate = FileField('Certificate', validators=[FileRequired(),FileAllowed(['jpg','png','pdf'])])#For certificate

    submit = SubmitField('Submit')

    def validate_duplicate(self, training_course, date):
        training = Training.query.filter_by(training_name=training_course.data,date=date.data).first()
        mv = ManagerVerification.query.filter_by(training_name=training_course.data,date=date.data).first()
        if training or mv:
            raise ValidationError('This is a duplicate training record')

【问题讨论】：

标签： flask flask-sqlalchemy flask-wtforms wtforms

【解决方案1】：

在 Wtforms 文档中，如果你想创建一个自定义验证器，你需要在 FlaskForm 类中创建一个当前名称为 'validate_ + {your field name}' 的函数，FlaskWtf 将传递整个表单和字段，我认为这是代码将为您工作

class add_training_form(FlaskForm): #All fields are required
    training_course = SelectField('Training Course', choices=[], validators=[DataRequired()]) #The choices will be assigned in route
    training_provider = SelectField('Training Provider', choices=[], validators=[DataRequired()])
    date = DateField('Date of Training', validators=[DataRequired()])
    cpd = IntegerField('CPD hours',validators=[DataRequired(message='Invalid input')] )
    certificate = FileField('Certificate', validators=[FileRequired(),FileAllowed(['jpg','png','pdf'])])#For certificate

    submit = SubmitField('Submit')

    def validate_training_course(form, training_course):
        training = Training.query.filter_by(training_name=training_course.data,date=form.date.data).first()
        mv = ManagerVerification.query.filter_by(training_name=training_course.data,date=form.date.data).first()
        if training or mv:
            raise ValidationError('This is a duplicate training record')

【讨论】：